In the closest packed struture of a metallic lattice , the number of mearest neighhours of a metallic atom is

Options

A. 12
B. 4
C. 8
D. 6

Answer

To solve the question regarding the number of nearest neighbors of a metallic atom in the closest packed structure of a metallic lattice, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Coordination Number**:
The coordination number of a metallic atom in a crystal lattice refers to the number of nearest neighboring atoms surrounding it.

2. **Identify the Closest Packed Structures**:
The two primary types of closest packed structures in metallic lattices are:
- Hexagonal Close Packing (HCP)
- Cubic Close Packing (CCP), also known as Face-Centered Cubic (FCC)

3. **Determine the Coordination Number for HCP and CCP**:
- In both HCP and CCP arrangements, each metallic atom is surrounded by 12 other atoms. This means that the coordination number for both structures is 12.

4. **Consider Other Structures**:
- It is also important to note that in other types of packing, such as Body-Centered Cubic (BCC), the coordination number is 8. However, the question specifically asks about the closest packed structures.

5. **Conclude the Answer**:
Since HCP and CCP both have a coordination number of 12, we can conclude that the number of nearest neighbors of a metallic atom in the closest packed structure is 12.

### Final Answer:
The number of nearest neighbors of a metallic atom in the closest packed structure of a metallic lattice is **12**.

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